<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <h1>hello,world</h1>
    <script>
        // alert("hello world")
        var s1="hello",s2="world";
        console.log("hello,world");
        console.log(s1)
        console.log(s2)
        var a="100",b="200"
        console.log(a+b)
    </script>
</body>
</html>